WISCONSINAN MOLLUSCAN FAUNAS 



31 



Pleistocene Series Thickness 



Wisconsinan Stage (feet) 



Woodfordian Substage 

 Peoria loess 



8. Loess, leached, tan, well developed soil profile in 



upper part. 5.0 



7. Loess, calcareous, gray, grading upward into yellow-tan, 

 massive; lower 5 feet contains abundant snail fauna 

 (locality 3). (P-526, lower; P-527, upper). 20.0 



Altonian Substage, or older 



6. Sand, very fine, and coarse silt, pale chocolate-brown 



to medium gray-pink, noncalcareous, massive; gradational 



at base with A-horizon below and erosional unconformity 



at top (P-525). 3.0 



5. Silt, massive, dark gray-brown, grading upward into dark 



gray A-horizon of A-C soil profile at top (P-523 lower; 

 P-524 upper). 5.0 



Pre-Wisconsinan Stages 



4. Soil, A-horizon; silt with some clay, dark gray-brown, 



crumb-structure, gradational at base (P-522). 1.0 



3. Soil, B-horizon; silt and clay, red-brown, tough, columnar 



structure, gradational (P-521). 3.0 



2. Silt, massive, noncalcareous, locally some fine sand, 



yellow-tan; locally a few scattered pebbles of chert 

 (P-520). 4.0 



1. Sand and silt, irregularly bedded, tan to brown, non- 

 calcareous (P-519); rests on weathered Maquoketa Shale. 2.0 



Total Pleistocene 43.0 



WEDRON SECTION 



Southwest end of quarry of Wedron Silica Company, as exposed on July 27, 1959, in 

 vertical face; SE^ SE^ SWi sec. 9, T. 34 N., R. 4 E. , La Salle County, Illinois. 

 Measured by John C. Frye, A. Byron Leonard, and H. B. Willman 



Pleistocene Series Thickness 



Wisconsinan Stage (feet) 



Woodfordian Substage 



Richland loess, Farm Ridge till, etc. 



7. Loess, till, and gravel, weathered and partly obscured 



by spoil pile. 6.0 



Cropsey till 



6. Till, oxidized, tan, poorly exposed. 5.0 

 Bloomington till 



5. Till, pink, bouldery, massive, calcareous, tough; 



indistinct boulder pavement in middle part. 15.0 



Shelbyville till 



4. Till, gray and tan, calcareous, bouldery, compact, sharp 



contact at top with an indistinct boulder pavement in top. 3.0 

 Pro-Shelbyville outwash 



3. Sand and gravel, loose, tan, calcareous, locally cross- 



bedded and generally well bedded, irregular erosional 



contact at base. 10.0 to 20.0 



lamoss geological 



SURVEY « IBRARY 

 M jtf 28 1986 



